Defrosting signal for refrigerators



. 1937- H. J. WEISBERG ET AL 2,071,148

DEFROSTING SIGNAL FOR REFRIGERATORS Filed March 27, 1935 INVENTOR 1 I?azz efif fi ATTOR EY t Patented m. 16, 1931 ,PATENToFI-ICE ,DEFROSTINGSIGNAL iron j nnmrcnnarons Harold J. Weisbcrg, ism-neon, and Charles E.Ide,

Greece, N. Y.

Application March 27, 1935, Serial No. 13,306

Y ZClaims. (o 171-311),

. The so-called electric refrigerators are pro vided with a freezingunit' comprising,one or more coils of pipe, which are part of therefrigerating apparatus-byfwhich the low tempera-* 'ture is secured inthe refrigerator. The moisture of the air condenses on these pipes and.freezes thereon, forming a coating of frost or ice thereon. This frost.is not .as-good a conductor of heat as is the pipe or pipes which itcovers, and it therefore interferes with the absorption of heat from theatmosphereof the refrigerator and interferes with the efficiency of therefrigeration. From timeto time this frost must be removed from thecoils of pipe, which is,easily done by simply turning off the-current,which permits the coils and the frost to gradually warm up, so that thefrost melts off or is easily broken off of the pipes.. This is calleddefrosting the refrigerator and must be done from time to time.

,For the purpose of indicating that'a layer of ice has formed on thepipes sufflciently thick so that it should be removed therefrom, anindicatorhas been provided which indicates that the frost or ice is ofobjectionable thickness and should be removed from the pipes. A

The ordinary electric refrigerator that is used in private homes isprovided with a door which closes the open space inside the refrigeratorin which food is.kept. Many ofsuch refrigerators are provided with alamp inside the refrigerator which lights only when thedoor is open,that is,

a the opening of'the door closes a switch which causes the .lamp tolight up when the door is opened, and opens the switch, or causes thelight'to go out, when the door is closed.'

One of the objects of our invention is to provide a special lightinsideor outside of the refrigerator that will light on the opening of thedoor only when thepipes should be defrosted.

Another'object of the invention is to make the accumulation-of icecomplete thecircuit so that the auxiliary light will light up, andindicatev that the refrigerator should be defrosted, when the .door isopen.

These and other objects of the invention will be illustrated in thedrawing, described in the specification and pointed out in the claims atthe end thereof.

In the drawing:

Figure 1 is a front elevation of the freezin Y unit, with the lampcircuits therefor.

Figure 2 is a side elevation of the freezing unit.

In the drawing like reference numerals indicate like parts.

g In the drawing reference'numeral I indicates the housing of thefreezing unit. 'This housingis closed at the front by a door 2; Pans ofwater can be placed in this housing for the purpose of turning it intoice. Below this housing is placed This housing is supported from thestructure one side of the freezing unit depend brackets I,

which brackets extend down along the side of the freezing unit. On thesebrackets is supported a cross bar 8, which is preferably made ofinsulating materiahsu'ch as bakelite, porcelain, etc. On this crossbaris mounted a strip of brass 9, or other conducting material, which brassis suitably spaced from the refrigerating unit or the coils thereof, sothat an air gap of predetermined width ordinarily exists between them.This brass strip is connected by the conductor l0 1:0 the conductor H.The conductor i 2 is connected to the conductor l3 by the switch I,which isoperated by the door.

When the door is opened the conductor I3 is energized, and energizes thelamp l5 and the conductor l6, which is grounded on the housing. Thecircuit of the lamp l5, however, remains open until the layer of ice I1forms sui'hciently thick to bridge the gap between the brass plate andthe housing I or one or more of the coils 4 thereof. This layer of icecloses the circuit and causes the lamp ii to light when the door isopened, or when the switch I4 is otherwise closed.

' of the refrigerator by the posts 5 and 6. Two or .four of these'postsare used, depending on the type of the refrigerator. From the posts 5, 5on thickness as to interfere with the efficiency of I the refrigeration,and the freezing unit should be defrosted. This is done by shuttingofhthe current from the refrigerator. When the defrosting is complete,and the current is turned on again, the lamp l5 will remain dead untilthe frost has accumulated to a sufficient thickness to again make itdesirable to defrost the refrigerator. Thereafter it will again light upuntil the frost or ice has been removed.

The lamp i5 can be either on the outside or inside of the refrigerator,and can be operated independently of the lamp l8. So far as this lamp I5is concerned, the switch M can be kept permanently closed or may beomitted altogether, that is, the circuit may be fully establishedwithout the switch, but the switch is shown because it is sufficient forthe signal to light merely on the opening of the door. This means savingof current.

If the switch I4 is closed, or is omitted from the circuit, the currentwill flow as soon as the least amount of frost accumulates and makescontact with the contact plate. In such case the current would melt thefrost and break the contact. With the switch normally open, no currentcan flow and the frost can accumulate until the contact is fullyestablished, with no possibility of melting the frost by resason of theflow of any current. When the switch is closed by the door, orotherwise, after the frost has fully accumulated the current can flowand the lamp will light, and during the short time that the door is openthe flow of current cannot melt the frost sufiiciently to break thecircuit or put out the special lamp that indicates that the freezingunit should be defrosted.

To avoid melting the frost and avoid interfering with the circuit thatis closed by it when the current flows, a small lamp is used, that is,one that has a small consumption of watts.

This device applies to any mechanical refrigeration as well as toelectrical refrigeration.

We claim:

1. In an electric or mechanical refrigerator the combination of afreezing unit on which frost is adapted to accumulate, a large contactplate suitably spaced from said freezing unit and insulated therefrom, alamp circuit connected to said freezing unit and said contact plate,said circuit being closed between the freezing unit and the contactplate by the accumulation of frost on the freezing unit, said lampcircuit having a lamp therein capable of lighting with a low consumptionof watts.

2. In an electric or mechanical refrigerator the combination of afreezing unit on which frost is adapted to accumulate, a large contactplate suitably spaced from said freezing unit and insulated therefrom, alamp circuit connected to said freezing unit and said contact plate,said circuit being closed between the freezing unit and the contactplate by the accumulation of frost on the freezing unit, a switch insaid circuit by which the circuit may be otherwise opened and closed;said lamp circuit having a lamp therein capable of lighting with a lowconsumption of watts, said switch being normally open.

HAROLD J. WEISBERG.

